Eye-testing apparatus



Sept. 9.1924,.-

w. i=. REAVES EYE TESTING APPARATUS Originai mafia- 4, 1922 Patented Sept. 9, 1924.

UNITED STATES PATENTOFFICE.

WILLIAM P. REAVES, F GREENSBORO, NORTH CAROLINA.

EYE-TESTING APPARATUS.

Application filed May 4, 1922, Serial No. 558,498. Renewed August 2, 1924.

To all whom it may camera: 7

Be it known that I, l/VILLIAM P. Rnnvns, a citizen of the United States, and residing at Greensboro, in the county of Guilford, State of North Carolina, have invented certain new and useful Improvements in Eye- Testing Apparatus, of which the following is a specification.

The present invention relates to an eye testing apparatus and particularly to devices of meridian dial type designed for testing eyes for astigmatic errors of refraction.

The object of the invention is to provide a device of this character in which the meridian lines may be varied in thickness as desired, thus avoiding the necessity for using a series of charts having lines engraved thereon, the lines of the several charts being of different values as measured in visual acuity units. v

In accordance with the present invention a frame is provided having mounted thereon a plurality of rotatable strips extending radially from a common center and preferably arranged at angles at intervals of throughout a semicircle. These strips are of rectangular cross section and appear as fine lines when their edges are presented to the observer and as relatively thick lines when the sides of the strips are visible to the observer. Means is provided for rotating the strips to any desired position so that their apparent thickness may be varied as desired from a minimum in which the edge of the strip alone is visible, to a maximum in which the side of the strip is visible.

The invention may be formed in various ways and is not limited in its scope to the form illustrated in the accompanying drawings and herein disclosed in detail, which is given by way of example. In the drawings:

Figure 1 is a front elevation of the dial showing one adjustment of the rotatable meridian strips;

Figure 2 is a view of a portion of the dial showing another adjustment of the strips;

1 Figure 3 is a section on line 33 of Figure 1 to a larger scale;

Figure 4 is a section on line fr-4: of Figure 1 to a larger scale; and

Figure 5 is a section on line 5-5 of Fig ure 4.

The frame comprises essentially two concentric semicircular members and 11 respecetively, the ends of which are connected and secured together by cross pieces 12. A I thlrd semicircular member also concentric with memberslO and 11 is indicatedfat13, the ends of this member being secured to the cross pieces 12. Both members constitute a protective guard but may be omitted if desired. A plurality of meridian ma strips being rotatably mounted in suitable apertures in the members 10 and 11 and fixed t0 the outer end of each stripis [a pinion 15.* The pinions 15 disposed to. the left of the vertical centerline of the appara tus (Figure 1) mesh with the left hand portion of a tWopart arcuate rack l6 which has 3 a plurality'of' slots 17 to receive screws18 which constitute guides and securing devices therefor. The central pinion 15 meshes with an extension 19 of the right hand portion of the rack which overlaps the adjacent end of the left hand portion, as. shown in Figure 5. It can thus be seen that upon'movementof the two portions of the rack toward or from each other the meridian strips 19'will be rotated and as these strips are relatively wide as compared with their thickness, such rotation causes them to appear to vary in thickness to an observer positioned in front of the apparatus.

Means for manually adjusting the rotatable strips by simultaneously moving the rack circumferentially is provided by means v of which the operator by a simple movement of a lever can readily secure the desired ad justment. Each rack is provided at its lower end with a pin 20 which projects through an arcuate slot 21 in a rotatable cam member 22 rigidly mounted upon a shaft 23 mounted in bearings 24: in the frame. Rotation of the shaft 23 is efiected by means of an operating lever 25 towhich a control cord or pulley may be secured if desired so that the device may be operated from a distant point. Ro-

tation of shaft 23, it will be seen, causes circumferential movement of the two portions of rack 16 simultaneously toward or away from each other and results in simultaneous rotation of the meridian strips 14,;

those strips to the right hand side of the center of the apparatus, however, rotating in a direction opposite to the direction of rotation of the strips on the left hand side. It will be seen that by manipulating the control lever meridian lines of any desired width within the limits of the apparatus will be presented to the eye of the observer stationed in front of the same. It is there fore unnecessary to use a plurality of charts having meridian lines engraved thereon as has heretofore been suggested.

It is possible to use the apparatus in various ways. Thus it may be placed in front of an illuminating field so that the meridian strips appear in silhouette to the eye of an observer. On the other hand, the meridian strips may be fabricated of light colored material or painting and the background or field may be relatively dark so that the strips appear to the observer as light colored lines in front ofa dark field. The meridian strips may be formed in still other ways and the apparatus may be illuminated from-the front if found desirable. A person skilled in the art will thus i'indit adapted to be utilized in a number of different ways, and in conjunction with other charts, such as the well known Snellen chart. v

To one skilled in the art it will also be apparent that the spirit of the invention may be embodied in a number of different forms of apparatus.

Having thus describedmy invention What I claim as new and desire to secure by Letters Patent is:

1. Aniastigmatic dial including in combination, a frame, a plurality of radially arranged strips having, two unequal dimensions in cross section and rotatably mounted in the frame, and means to rotate the strips to cause them to ap ear to an observer as lines of different wit ths.

2. An astigmatic dial including in combination, a frame, a plurality of radially arranged strips having two unequal dimensions in cross section and movable in the frame, and means to rotate the strips to cause them to appear to an observ'eras lines of different widths. V

3. An astigmatic dial including in combi nation, a frame, a plurality of radially arranged strips having two unequal dimensions in cross section and spaced at equal angular intervals, said strips being rotatably mounted in the frame, and means to rotate the strips to cause them to appear to an observer as lines of different widths.

4. An astigmatic dial including in combination, a frame, a plurality of radially arranged strips having two unequal dimensions in cross section and spaced at angles of 5 apart, said strips being rotatably mounted in the. frame, and means to rotate the strips to cause them to appear to an observer as lines of different widths.

5. An astigmatic dial including in combination, a frame, a plurality of radially arranged strips of substantially rectangular cross section and rotatably mounted in the frame, and means to rotate the strips to cause them to appear to an observer as lines of different widths.

6. An astigmatic dial including in combi nation, a frame, a plurality of radially arranged strips having two unequal dimensions in cross section and rotatably mounted in the frame, and means including a manu ally operable cam to rotate the strips to cause them to appear to an observer aslines of different widths.

7. An astigmatic dial including in combination, a frame, a plurality of radially arranged strips having two unequal dimensions in cross section and rotatably mounted in the frame, and means to rotate the strips to cause them to appear to an observer as lines of different widths including a'pinion secured to each strip, a rack engaging the pinion, and means for operating the rack. 8. Eye testing apparatus including in combination, a frame, a plurality of objects having two unequal dimensions in cross section and movably mounted in the frame, and means to move said objects to cause them to appear to an observer to vary in width.

9. Eye testing apparatus including in combination, a frame, an object movably mounted on the frame and having two unequal dimensions in cross section, and means to move said object to cause it to appear to an observer as varying in width.

In testimony whereof I hereunto itffiX my signature.

WILLIAM P. REAVES. 

